From ae813a00c8bc450a61c453152ed70ea165c8fb8a Mon Sep 17 00:00:00 2001
From: Adam Dinwoodie <adam@dinwoodie.org>
Date: Wed, 18 Feb 2026 10:50:58 +0000
Subject: [PATCH] nixos-install-tools: handle spaces in mount paths

If a btrfs or bcachefs mountpoint has a space or some other special
characters, these will mangle the command that nixos-generate-config
runs to get information about the mount.  Avoid this by switching from
the "magic" form of calling the `open` function to the "three-argument"
form, where each command argument is specified separately.

https://perldoc.perl.org/functions/open#Whitespace-and-special-characters-in-the-filename-argument

Fixes #491738
---
 nixos/modules/installer/tools/nixos-generate-config.pl | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/nixos/modules/installer/tools/nixos-generate-config.pl b/nixos/modules/installer/tools/nixos-generate-config.pl
index 96d0d68e5c93..ac406d2dfce3 100644
--- a/nixos/modules/installer/tools/nixos-generate-config.pl
+++ b/nixos/modules/installer/tools/nixos-generate-config.pl
@@ -24,8 +24,7 @@ sub uniq {
 }
 
 sub runCommand {
-    my ($cmd) = @_;
-    open FILE, "$cmd 2>&1 |" or die "Failed to execute: $cmd\n";
+    open FILE, "-|", @_ or die "Failed to execute: @_\n";
     my @ret = <FILE>;
     close FILE;
     return ($?, @ret);
@@ -458,7 +457,7 @@ EOF
 
     # Is this a btrfs filesystem?
     if ($fsType eq "btrfs") {
-        my ($status, @info) = runCommand("@btrfs@ subvol show $rootDir$mountPoint");
+        my ($status, @info) = runCommand("@btrfs@", "subvol", "show", "$rootDir$mountPoint");
         if ($status != 0 || join("", @info) =~ /ERROR:/) {
             die "Failed to retrieve subvolume info for $mountPoint\n";
         }
@@ -505,7 +504,7 @@ EOF
     # This should work for single and multi-device systems.
     # still needs subvolume support
     if ($fsType eq "bcachefs") {
-        my ($status, @info) = runCommand("@bcachefs@ fs usage $rootDir$mountPoint");
+        my ($status, @info) = runCommand("@bcachefs@", "fs", "usage", "$rootDir$mountPoint");
         my $UUID = $info[0];
 
         if ($status == 0 && $UUID =~ /^Filesystem:[ \t\n]*([0-9a-z-]+)/) {